Latch



March zo, .1934. EyG, PROST 1,951,628

' INI/NTOR. [dn/0rd G. Pros ATTORNEYS.

March 20, 1934. E. G. PRosT 1,951,628

LATCH Filed April 25, 1933 4 Sheets-Sheet 2 :F1 I E E INVENTOR. fdl/voro 6*'. ,f7/"051 ATTORNEYS.

March 20, 1934. E. G. PRosT 1,951,628

LATCH Filed April 25, 1935 4 Sheets-Sheet 3 PlEnn-'E- INV ENTOR. fdl/Vara C?. Pros A TTORNE YS,

March 20, 1934. E G FROST 1,951,628

' LATCH Filed April 25, 1953 4 Sheets-Sheet 4 I @I i FJLE. E

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ATTORNEYS.

Patented Mar. 20, 1934 UNITED STATES PATENT oFFlcE Claims.

My invention relates to means for latching or locking relatively movable elements in a predetermined position, and is especially concerned Withan automatic latch operative upon the occurrence of a predetermined condition.

Although my invention is susceptible to application in various different environments, it is particularly useful in connection with filing cabinets which are widely used for the storage of val- 10 uable and semi-valuable documents. Ordinarily,

such documents must be frequently referred to, so that the customary filing cabinet includes a plurality of drawers for retaining the filed material. The drawers are quite freely slidable with respect to the cabinet frame or casing for ease and facility of access to the contacts. When a hazardous condition, such as a fire, arises, a filing cabinet may be dislodged or otherwise displaced from its normal position of rest, andsthe freely slidable drawers may be impelled from their normal, closed position to an open position thereby exposing the contents of the cabinet. Under average conditions of use the drawers of the cabinet must be operated so frequently that an ordinary latch mechanism is impractical because of the added dimculty. of gaining access to the iiles. Types of latches which can be left in unlatched position, although affording easy access to the files, are naturally of no avail when an unusual condition, such as a fire, arises.

It is therefore an object of my invention to provide a latch especially applicable to a filing cabinet, which will hold the cabinet in a safe condition during a fire or comparable hazard.

Another object of my invention is to provide means for retaining an enclosure, such as a cabinet, inclosed condition automatically.

An additional object of my invention is to provide a means responsive to temperature for latching a cabinet in closed position.

A further object of my invention is to provide a latch which is easily applicable to the standard forms of filing cabinets now available, for automatically latching such cabinets in closed position.

A still yfurther object of my invention is to improve, in general, tiling cabinets and comparable structures.

The foregoing and other objects are attained in the embodiment of the invention shown in the drawings, in Which- Figure 1 ,is a cross-section on a vertical, longitudinal plane of a filing cabinet incorporating a latch of my invention.

Figure 2 is a cross-section on a vertical, longitudinal plane of a portion of a filing cabinet incorporating a modied form of my invention.

Figure 3 is a front elevation of the upper portion of a filing cabinet, portions being broken away to disclose the interior construction incor- 80 porating a further modified form of latch of my invention.

Figure 4 is a front elevation of the upper portion of a filing cabinet, a portion being broken away to disclose an additional modification of my invention incorporated in the cabinet.

Figure 5 is a cross-section the plane of which is indicated by the lines 5-5 of Figure 4.

Figure 6 is an elevation, with a portion broken away, showing a modified form of my latch.

In its preferred form, the latch of my invention includes a casing with respect to which a closure is movable from a closed position, with which is combined a latch member for securing the closure in said closed position in response to a predetermined thermal condition.

Although the latch of my invention is susceptible to embodiment in various different structures, I have chosen to disclose it herein as it is preferably incorporated with a iling cabinet or safe cabinet of the flreproof or fire resistant, and usually metallic types recognized as standard. For instance, in Figure 1 I have disclosed a cabinet, generally designated 6, having a casing or framework 'I fabricated of sheet metal 65 shapes in the customary way and providing an enclosure within which a plurality of drawers 8 is disposed. 'I 'he drawers are slidable from closed. position, in which they are shown in Figure 1,

to an open position projecting from the casing 7, and move through apertures 9 provided in the casing for that purpose. Except for the apertures 9 the casing is preferably closed and affords protection against lire.

The drawers 8 themselves are each preferably 95 provided with a front plate 11 or closure which is adapted, when the drawer is in closed position, to occupy the adjacent aperture 9 and to provide an eil'ective sealfor the contents of the cabinet against re and comparable deleterious influences. Each of the drawers 11 preferably is provided with a handle 12 for convenience in manipulation and is disposed for slidable movement on runners 13 which may be provided with anti-friction devices such as rollers, not shown. The drawers also include side plates 14 as well as end plates 16.

In accordance with my invention, I preferably provide adjacent to each of the drawers 8 a latch member 17 which in the present instance 110 takes the form of a hook, adapted in one position to engage the rear wall 16 of the adjacent drawer, and in another position to clear the rear wall 16 so that the drawer is freely slidable. All of the latch members 17 are preferably designed for simultaneous actuation, and therefore each member 17 is mounted on a latch bar 18 guided in apertured angles 19 secured to the casing 7. When the latch bar 18 is translated downwardly, as seen in Figure l, all of the latch members 17 are in engagement with their respective drawers 8 and prevent withdrawal thereof from closed position. In order to urge the latch bar 18 in this direction, and hence to a latching position, I preferablydispose a coil spring 2l at a convenient location in the casing 7 and fasten one end 22 of the coil spring to the terminus of the latch bar 18 and fasten the other end 23 of the coil spring to an apertured projection 24 secured to the casing 7.

In order to render the spring 21 normally ineffective so that the latch members 17 are normally out of engagement with the `several draw ers 8, and in order to ensure latching of the drawers in closed position in the event of fire, I preferably provide a thermally responsive means to control the latch bar 18. In the present instance such means takes the form of a fusible link 26 which at one end engages a hook 27 projecting from the latch bar 18, and at the other end engages a hook 28 secured to the casing 7. The link 26 is of such length that the latch members 17 are held upwardly out of engagement with the rear walls 16 of the drawers, but .the material of the fusible link 26 is such that it melts at a predetermined temperature. Upon melting of the link, the spring 21 is effective to translate the latch bar 18 and to cause engagement of the several latch members 17 with their respective closures 8.

With this structure, therefore, the drawers are all latched in closed position if the temperature rises above the predetermined temperature at which the fusible link 26 melts. Despite dislodgment of the cabinet under adverse conditions from its upright, normal position, the drawers are held against displacement, but, nevertheless, under normal conditions the drawers are as freely slidable and access to the contents of the cabinet is as facile as with the standard filing cabinet.

Since the fusible link melts, having released the latch bar 18 once it is incapable of restoring the latch bar to its former position, so that, despite reduction` in temperature* after a predetermined temperature has once been exceeded, the drawers are still locked or latched. In order that the drawers can subsequently be released, and also in order that the fusible link can be replaced and the cabinet restored to its original condition, I preferably dispose a removable closure plate 29 over an aperture 31 in the casing 7 adjacent to the location of the link 26, so that a new link can readily be installed after the latch bar 18 has been translated upwardly against the urgency of the spring 21 into its former position with the latch members 17 out of engagement with the various drawers.

In the form of latch of my invention disclosed particularly in Figure 2, I have shown an arrangement in which the file cabinet is provided with a key lock and in which the rear wall of the drawers is not utilized for latching purposes. In this arrangement there is provided a cabinet-.casing 36 of generally standard form, Within whichapluralty of closure drawers 37 is adapted to move from a closed position toward open position. Customarily, the cabinet is provided with a latch bar 38 disposed rearwardly of the drawers 37 and guided in supports 39 secured to the casing 36. The latch bar 38 is provided with a plurality of latch members 41 of hook-like formation which in one position are adapted to be free of the drawers 37 and in another position are adapted to pass through apertures 42 in the drawers and interengage with the bottom member 43 of the respective drawers. The latch bar 38 is urged upwardly into latching position by a spring 44 one end of which is engaged with a hook 46 on the latch bar 38 and the other end of which is engaged with a bracket 4'7 secured to the casing 36.

For manipulating the latch bar 38 there is provided a lock bar 48 at one end connected to a standard key lock 49 having an operating button 51 incorporated therewith for actuation by hand. 'I'he lock bar 48 is translatable between two extreme positions by manipulation of the push but ton 5l, in one of the positions the lock 49 taking effect to hold the lock bar which is released upon Aunlocking of the lock 49. A spring 52, at one end abutting a collar 53 on the lock bar and at the other end abutting a bracket 54 secured to the casing 36 and also supporting the lock bar 48, is effective to urge the lock bar towards unlocked position.

In order to be effective upon the latch bar 38, the lock bar 48 at one'extremity carries a cam plate 56 which is provided with a notch 57 designed to receive the upper terminus 58 of the latch bar 38. When the push button 51 is pressed toward the casing 36, the lock bar 48 is translated against the urgency of the spring 52, and the cam plate 56 is moved so that the notch 57 overlies the terminus 58 of the latch bar 38. The spring 44 is then effective to lift the latch bar 38 so that the latch members 41 pass through the apertures 42 in the drawers and hold them in locked position. When the lock 49 is unlocked, the spring 52, having an urgency superior to that of the spring 44, is effective to translate the lock bar 48 in the opposite direction and to cause the cam plate 56 to displace the latch bar 38 against the urgency of the spring 44 and remove the latch members 41 from their respective apertures, thereby releasing the drawers.

In accordance with my invention, I provide means which are thermally responsive for locking or latching thel drawers in closed position. To this end, on the lock bar 48 I preferably mount a collar 61 which, when the lock bar 48 is in unlocked position, just abuts a sleeve 62 connected to one end of a fusible link 63. nected to a bracket 64 secured to the casing 36, and is likewise connected to a spring 66 fastened to a bracket 67 on the casing 36. The force of the spring`66 is superior to that of the spring 52 and is superior to that of the spring 44.

When the temperature exceeds a predetermined amount, the fusible link 63 melts and permits the spring 66 to be effective to translate the sleeve 62. In the event the lock bar 48 is in locked position, the sleeve 62 rides over against the collar 61 and prevents the lock bar from moving to unlocked position even though the lock 49-is unlocked. On the other hand, in the event the button 51 and the lock bar 48 are in unlocked position, the force of the spring 66 is of suflicient magnitude to translate the sleeve 62 axially against the collar 61 and therefore to translate The link is con' projects through a slot 82 in the front face of in the cabinet casing '72.

the lock bar 48 and in the normal way to cause the latch members 41 to interengage with the respective drawers 37. With this arrangement, while the cabinet is a standard one, provided with a key lock which can be operated as usual, it is,

in accordance with my invention, supplementedwith a latch responsive to thermal conditions which is eiective, no matter whether the cabinet is locked or unlocked, to ensure that -the respective drawers are latched in closed position.

In Figure 3 I have shown a different arrangementin which the individual drawers '71of the cabinet casing '72 are provided with latch members '73. The latch member '73 is guided in the structure 74 of the closure or drawer '71 and is adapted to occupy any one of three positions. In the position indicated by the dotted line '76 the latch bar 73 is fully projected and passes through an aperture 7'7 in the casing '72 in order to latch the casing and closure 71 in latched position. The latch member 73 is urged toward such latched position by a coil spring 78 situated between the structure '74 and an enlarged terminus '79 on the latch member. A

By manipulation of a thumb button 81 which the drawer '71, the latch member 73 can be moved from the latched position indicated by the line 76 into an unlatched position indicated by the dotted line 83. By manipulation of the thumb button 81 at the proper time, the drawer '71 can be projected from and retracted into the casing cabinet and can be latched in closed position for each operation. In the event, however, that such latching manipulation becomes disadvantageous due to frequent use of the drawer '71, the thumb button 81 can be used to translate the latch member 73 into a third position, indicated at 84 in which the spring 78 is rendered ineiective by a lever 86 pivotally mounted as at 8'7 on the structure '74 of the drawer and at its terminus adapted to interengage a notch 88 in the latch member '73. A spring 89 normally urges the lever 86 against the latch member `'73, and the cam action of the notch 88 with respect to the lever 86 is such that, while the bias of the spring 78 is resisted, a superior manual force on the member 81 is effective to displace the lever 86 and permit the latch member 73 to be returned to either of its other positions.

In the event, however, that the latch member 73 should inadvertently be left in a position such as 84, I provide means for latching the drawer '71 in the casing 72 upon the occurrence of a predetermined temperature. To this end there is disposed in the structure '7,4 of the' drawer a thermally expansive cell 91 which at one end is anchored as at 92 to the structure '74 and `at the other end abuts the lever 86, so that at temperatures above a predetermined temperature expansion of the cell 91 is eiective to pivot the lever 86 about its pivot point 87 and against the urgency of the spring 89, thereby withdrawing the lever from the notch 88 and permitting the spring 78 to be effective to translate the latch member '73 from the position indicated at 84 into the position indicated at '76, thus completely latching the drawer '71 in closed position In this form of the latch, -if a predetermined temperature is once exceeded, the latch is effective to hold the drawer and the casing in relatively closed position, and after such an abnormal temperature has passed it is necessary manually to unlatch the members for further normal use. It is, however,

not necessary to renew any element, such as a fusible link.

In some instances, in place of the fusible link type of thermal responsive mechanism, and instead of the expanding cell type of temperature responsive device, I prefer to use a thermostat of the bimetallic style. In such case, each of the drawers 96 of a cabinet casing 9'7 is provided with a latch member 98 suitably mounted in the drawer structure 99 for translatory movement from a retracted position as shown in full lines, ioa projected position as shown in dotted lines 101, in interengagement with the structure of the casing 97. A coil spring 102 is eiective to translate the latch member 98 into projected lposition to latch the drawer and the casing together, but is normally rendered ineffective by a bimetallic strip 103 which is anchored as at 104 to the structure 99 of the drawer and at the other end and under normal conditions of temperature projectsl into a notch 106 cut in the latching member 98. Upon the occurrence of an abnormally high temperature the bimetallic strip 103 is displaced from its normal rectilinear form into a curved form, indicated by the dotted lines 10'7, and in changing its shape moves out of the notch 106 thereby releasing the latch member 98 to be translated by the spring 102 and to latch the drawer 96 firmly in closed position in the cabinet casing 97. The latch structure can be so enclosed as to require mutilation of the cabinet for reopening after a fire or can be at least in part accessible for re-cocking by hand or a suitable tool.

As shown in Figure 6, a standard form of ille cabinet can be altered to incorporate my invention. In this embodiment there is provided a cabinet casing 111 in which a drawer 112 is movable. The drawer includes a closure plate 113 having double walls between which is included a latching mechanism. Latch members 114 and 116 are adaptedto be oppositely trans-y lated between latched and unlatched positions. The latch members are urged by a spring 117 outwardly to occupy recesses 118 and 119 in the casing 111 and partake of equal and opposite movement since each of the latch members is provided with a gear rack 121 meshing with an intermediate gear 122 mounted for rotation on the closure plate 113. The latch member 114, for instance, is provided with a thumb button 123 piercing the plate 113 adjacent a handle 124 for convenient operation. When the button 123 is suitably moved, the latch members are retracted to unlatched position against the urgency of the spring 117.

In order to disable the latching mechanism in unlatched position to facilitate rapid use of the lle but to insure latching of the drawer 112 in event of fire, I preferably insert a plug or wedge 126 of fusible metal in the closure plate 113 friotionally to retain the latch member 1 14, and hence the entire latching mechanism, in unlatched position. Upon a rise in temperature to a predetermined value, the fusible link or plug 126 melts and releases the latch member 114 thereby permitting the latching mechanism to latch the drawer 112 in closed position in the cabinet casing 111. y

I claim:

1. A latch comprising a cabinet casing; a drawer slidably mounted in said casing to move between open position and closed position, a latch for holding said drawer in saidl closed position,

means for rendering said latch ineffective, and thermally responsive means for disabling said rendering means.

2. A latch comprising a casing, a drawer constituting a closure for said casing and adapted to move between two extreme positions, a latch for constraining said drawer in one of said extreme positions, means for rendering said latch ineffective, and thermally responsive means for disabling said rendering means.

3. A latch comprising a cabinet casing a drawer movable in said casing, a latch member urged to hold said drawer against movement in said casing, and thermally responsive means for holding said latch member out of latching engagement.

4. A latch comprising a cabinet casing, a drawer movable in said casing, a latch member, means for urging said latch member into engagement with said drawer, and temperature responsive means for holding said latch member out of engagement with said drawer.

5. A latch comprising a cabinet casing, a drawer movable in said casing, a latch member, a spring for urging said latch member into engagement with said drawer, and a fusible link for holding said latch member out of engagement with said drawer.

6. A latch comprising a cabinet casing, a drawer movable in said casing, a latch member for holding said drawer against movement in said casing, means for urging said latch member into holding position, and thermally responsive means for holding said latch member out of holding position.

7. A latch comprising a cabinet casing, a plurality of drawers movable from a closed position in said casing, a latch bar in said casing, a plurality of latch members on said bar, each of said members being adapted to engage and hold an associated one of said drawers in said closed position, a spring engaging said bar and said casing for urging said bar to position said latch members in engagement with said drawers, and a fusible link engaging said bar and said casing for holding said bar to position said latch members out of engagement with said drawers.

8. A latch comprising a cabinet casing, a plurality of drawers movable from a closed position in said casing, a latch bar in said casing, latch members on said bar, each of said members being adapted to engage and hold an associated one of said drawers in said closed position, a spring engaging said casing and said bar for urging said bar to position said latch members in engagement with said drawers, a lock bar movable in said casing between two positions in one of which said latch bar is held to position said latch mem.- bers out of engagement with said drawers and in the other of which said latch bar is disengaged from said lock bar, a spring for urging said lock bar into said one position, a superior spring for urging said lock bar into said other position, and a fusible link for rendering said superior spring ineffective at temperatures below a predetermined temperature.

9. A latch comprising a cabinet casing, a drawer slidable in said casing, a latch' member mounted on said drawer, means for projecting said latch member to engage said casing, and a thermally responsive member forl holding said latch member in retracted position'at temperatures below a predetermined temperature.

10. A latch comprising a cabinet casing, a drawer slidable in said casing, a latch member mounted on said drawer, means inaccessible from the exterior of said drawer for urging said latch member to engage said casing, means accessible from the exterior of said drawer for manipulating said latch member, means for yieldably holding said latch member out of engagement with said casing, and temperature responsive means for rendering said holding means ineffective.

EDWARD G. FROST. 

